Molecular sieve catalyst compositions, their production and use in conversion processes

ABSTRACT

The invention relates to a catalyst composition, a method of making the same and its use in the conversion of a feedstock, preferably an oxygenated feedstock, into one or more olefin(s), preferably ethylene and/or propylene The catalyst composition a molecular sieve, such as a silicoaluminophosphate and/or an aluminophosphate, hydrotalcite, and optionally a rare earth metal component

FIELD

The present invention relates to molecular sieve catalyst compositions,to the production of such compositions and to the use of suchcompositions in conversion processes, particularly to produce olefin(s).

BACKGROUND

Olefins are traditionally produced from petroleum feedstocks bycatalytic or steam cracking processes. These cracking processes,especially steam cracking, produce light olefin(s), such as ethyleneand/or propylene, from a variety of hydrocarbon feedstocks. Ethylene andpropylene are important commodity petrochemicals useful in a variety ofprocesses for making plastics and other chemical compounds.

The petrochemical industry has known for some time that oxygenates,especially alcohols, are convertible into light olefin(s). There arenumerous technologies available for producing oxygenates includingfermentation or reaction of synthesis gas derived from natural gas,petroleum liquids or carbonaceous materials including coal, recycledplastics, municipal waste or any other organic material. Generally, theproduction of synthesis gas involves a combustion reaction of naturalgas, mostly methane, and an oxygen source into hydrogen, carbon monoxideand/or carbon dioxide. Other known syngas production processes includeconventional steam reforming, autothermal reforming, or a combinationthereof.

Methanol, the preferred alcohol for light olefin production, istypically synthesized from the catalytic reaction of hydrogen, carbonmonoxide and/or carbon dioxide in a methanol reactor in the presence ofa heterogeneous catalyst. For example, in one synthesis process methanolis produced using a copper/zinc oxide catalyst in a water-cooled tubularmethanol reactor. The preferred process for converting a feedstockcontaining methanol into one or more olefin(s), primarily ethyleneand/or propylene, involves contacting the feedstock with a molecularsieve catalyst composition.

There are many different types of molecular sieve well known to converta feedstock, especially an oxygenate containing feedstock, into one ormore olefin(s). For example, U.S. Pat. No. 5,367,100 describes the useof the zeolite, ZSM-5, to convert methanol into olefin(s); U.S. Pat. No.4,062,905 discusses the conversion of methanol and other oxygenates toethylene and propylene using crystalline aluminosilicate zeolites, forexample Zeolite T, ZK5, erionite and chabazite; U.S. Pat. No. 4,079,095describes the use of ZSM-34 to convert methanol to hydrocarbon productssuch as ethylene and propylene; and U.S. Pat. No. 4,310,440 describesproducing light olefin(s) from an alcohol using a crystallinealuminophosphate, often designated AlPO4.

Some of the most useful molecular sieves for converting methanol toolefin(s) are silicoaluminophosphate molecular sieves.Silicoaluminophosphate (SAPO) molecular sieves contain athree-dimensional microporous crystalline framework structure of [SiO4],[AlO4] and [PO4] corner sharing tetrahedral units. SAPO synthesis isdescribed in U.S. Pat. No. 4,440,871, which is herein fully incorporatedby reference. SAPO molecular sieves are generally synthesized by thehydrothermal crystallization of a reaction mixture of silicon-,aluminum- and phosphorus-sources and at least one templating agent.Synthesis of a SAPO molecular sieve, its formulation into a SAPOcatalyst, and its use in converting a hydrocarbon feedstock intoolefin(s), particularly where the feedstock is methanol, are disclosedin U.S. Pat. Nos. 4,499,327, 4,677,242, 4,677,243, 4,873,390, 5,095,163,5,714,662 and 6,166,282, all of which are herein fully incorporated byreference.

Typically, molecular sieves are formed into molecular sieve catalystcompositions to improve their durability in commercial conversionprocesses. These molecular sieve catalyst compositions are formed bycombining the molecular sieve with a matrix material and/or a binder,which typically are metal oxides. However, these binders and matrixmaterials typically only serve to provide desired physicalcharacteristics to the catalyst composition, and have little to noeffect on conversion and selectivity of the molecular sieve. It wouldtherefore be desirable to have an improved molecular sieve catalystcomposition having a better conversion rate, improved olefin selectivityand a longer lifetime.

U.S. Pat. No. 4,889,615 discloses a process for the catalytic crackingof high metals content feeds, including resids, in which the feed iscracked in the presence of a catalyst comprising a zeolite, such aszeolite Y, and an additive comprising a dehydrated magnesium-aluminumhydrotalcite which acts as a trap for vanadium as well as an agent forreducing the content of sulfur oxides in the regenerator flue gas.

U.S. Pat. No. 6,010,619 discloses a fluid catalytic cracking process forconverting hydrocarbon feed stocks containing heavy metal compounds, inwhich the catalyst employed comprises a zeolite orsilicophosphoaluminate treated with particles of a carbonatedstrontium-substituted hydrotalcite.

U.S. Pat. No. 6,180,828 discusses the use of a modified molecular sieveto produce methylamines from methanol and ammonia where, for example, asilicoaluminophosphate molecular sieve is combined with one or moremodifiers, such as a zirconium oxide, a titanium oxide, an yttriumoxide, montmorillonite or kaolinite.

EP-A-312981 discloses a process for cracking vanadium-containinghydrocarbon feed streams using a catalyst composition comprising aphysical mixture of a zeolite embedded in an inorganic refractory matrixmaterial and at least one oxide of beryllium, magnesium, calcium,strontium, barium or lanthanum, preferably magnesium oxide, on asilica-containing support material.

Kang and Inui, Effects of decrease in number of acid sites located onthe external surface of Ni-SAPO-34 crystalline catalyst by themechanochemical method, Catalysis Letters 53, pages 171-176 (1998)disclose that the shape selectivity can be enhanced and the cokeformation mitigated in the conversion of methanol to ethylene overNi-SAPO-34 by milling the catalyst with MgO, CaO, BaO or Cs2O onmicrospherical non-porous silica, with BaO being the most preferred.

International Publication No. WO 98/29370 discloses the conversion ofoxygenates to olefins over a small pore non-zeolitic molecular sievecontaining a metal selected from the group consisting of a lanthanide,an actinide, scandium, yttrium, a Group 4 metal, a Group 5 metal orcombinations thereof.

In our co-pending U.S. patent application Ser. No. 10/364,156 filed Feb.10, 2003, there is described catalyst composition which exhibitsenhanced lifetime when used in the conversion of oxygenates to olefinsand which comprises a molecular sieve and at least one metal oxidehaving an uptake of carbon dioxide at 100° C. of at least 0.03 mg/m2 ofthe metal oxide. The metal oxide is selected from an oxide of Group 4 ofthe Periodic Table of Elements, either alone or in combination with anoxide selected from Group 2 of the Periodic Table of Elements and/or anoxide selected from Group 3 of the Periodic Table of Elements, includingthe Lanthanide series of elements and the Actinide series of elements.

SUMMARY

In one embodiment, the invention provides a catalyst compositionincluding a molecular sieve, hydrotalcite, and a rare earth metalcomponent. In one aspect of this embodiment, the molecular sieve isselected from an aluminophosphate, a silicoaluminophosphate andmetal-containing forms thereof. In a particular aspect of thisembodiment, the rare earth metal is lanthanum.

Conveniently, the molecular sieve is selected from SAPO-5, SAPO-8,SAPO-11, SAPO-16, SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35,SAPO-36, SAPO-37, SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-56,AlPO-5, AlPO-11, AlPO-18, AlPO-31, AlPO-34, AlPO-36, AlPO-37, AlPO-46,MCM-2, metal-containing forms thereof and mixtures, includingintergrowths, thereof. Particularly useful molecular sieves includeSAPO-18, SAPO-34, SAPO-35, SAPO-44, SAPO-47, AlPO-34, metal-containingforms thereof, and mixtures, including intergrowths, thereof, especiallySAPO-34, intergrowths of SAPO-34 and SAPO-18, and intergrowths ofGeAPO-34 and GeAPO-18.

In another embodiment, the invention provides a catalyst compositionincluding an aluminophosphate or silicoaluminophosphate molecular sieveselected from SAPO-5, SAPO-8, SAPO-11, SAPO-16, SAPO-17, SAPO-18,SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37, SAPO-40, SAPO-41,SAPO-42, SAPO-44, SAPO-47, SAPO-56, AlPO-5, AlPO-11, AlPO-18, AlPO-31,AlPO-34, AlPO-36, AlPO-37, AlPO-46, MCM-2, metal-containing formsthereof, and mixtures, including intergrowths, thereof and hydrotalcite.Optionally, the composition can further include a rare earth metalcomponent, such as lanthanum.

Conveniently, the aluminophosphate and metalloaluminophosphate molecularsieves are selected from AlPO-5, AlPO-11, AlPO-18, AlPO-31, AlPO-34,AlPO-36, AlPO-37, AlPO-46, metal-containing forms thereof and mixtures,including intergrowths, thereof.

In yet another embodiment, the invention provides a process forformulating a molecular sieve catalyst composition, the processincluding providing a molecular sieve; providing a hydrotalcitecomposition including hydrotalcite and rare earth metal component; andcombining the molecular sieve and the hydrotalcite composition toproduce a formulated molecular sieve catalyst composition.

Conveniently, the step of providing a hydrotalcite composition iscarried out by providing a solution of a rare earth metal compound;mixing the solution with hydrotalcite to form a slurry; and drying theslurry to form a dried hydrotalcite composition. By way of example, therare earth metal compound may be a halide, an oxide, an oxyhalide, ahydroxide, a sulfide, a sulfonate, a boride, a borate, a carbonate, anitrate, a carboxylate or a mixture thereof.

Conveniently, the step of combining the molecular sieve and thehydrotalcite composition is carried out by forming a slurry of themolecular sieve and the hydrotalcite composition; and drying the slurryto form a dried, formulated molecular sieve catalyst composition.

In further embodiment, the invention provides a process for converting ahydrocarbon oxygenate feedstock to olefins, the process comprisingcontacting the feedstock with a catalyst composition comprising:

-   -   (a) molecular sieve; and    -   (b) hydrotalcite;        under catalytic conversion conditions, to form a product mixture        comprising olefins.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Introduction

The invention is directed to a molecular sieve catalyst composition, itsproduction and its use in the conversion of hydrocarbon feedstocks,particularly oxygenated feedstocks, into olefin(s). It has been foundthat combining a molecular sieve with hydrotalcite, optionally togetherwith a rare earth metal, results in a catalyst composition with a longerlifetime when used in the conversion of feedstocks, such as oxygenates,more particularly methanol, into olefin(s). In addition, the resultantcatalyst composition tends to be more propylene selective than the samemolecular sieve without the hydrotalcite additive.

Molecular Sieves

Molecular sieves have been classified by the Structure Commission of theInternational Zeolite Association according to the rules of the IUPACCommission on Zeolite Nomenclature. According to this classification,crystalline molecular sieves, for which a structure has beenestablished, are assigned a three letter code and are described in theAtlas of Zeolite Framework Types, 5th edition, Elsevier, London, England(2001), which is herein fully incorporated by reference.

Crystalline molecular sieves all have a 3-dimensional, four-connectedframework structure of corner-sharing [TO4] tetrahedra, where T is anytetrahedrally coordinated cation. Molecular sieves are typicallydescribed in terms of the size of the ring that defines a pore, wherethe size is based on the number of T atoms in the ring. Otherframework-type characteristics include the arrangement of rings thatform a cage, and when present, the dimension of channels, and the spacesbetween the cages. See van Bekkum, et al., Introduction to ZeoliteScience and Practice, Second Completely Revised and Expanded Edition,Volume 137, pages 1-67, Elsevier Science, B. V., Amsterdam, Netherlands(2001).

Non-limiting examples of molecular sieves are the small pore molecularsieves, AEI, AFT, APC, ATN, ATT, ATV, AWW, BIK, CAS, CHA, CHI, DAC, DDR,EDI, ERI, GOO, KFI, LEV, LOV, LTA, MON, PAU, PHI, RHO, ROG, THO, andsubstituted forms thereof; the medium pore molecular sieves, AFO, AEL,EUO, HEU, FER, MEL, MFI, MTW, MTT, TON, and substituted forms thereof;and the large pore molecular sieves, EMT, FAU, and substituted formsthereof. Other molecular sieves include ANA, BEA, CFI, CLO, DON, GIS,LTL, MER, MOR, MWW and SOD. Non-limiting examples of preferred molecularsieves, particularly for converting an oxygenate containing feedstockinto olefin(s), include AEL, AFY, AEI, BEA, CHA, EDI, FAU, FER, GIS,LTA, LTL, MER, MFI, MOR, MTT, MWW, TAM and TON. In one preferredembodiment, the molecular sieve of the invention has an AEI topology ora CHA topology, or a combination thereof, most preferably a CHAtopology.

The small, medium and large pore molecular sieves have from a 4-ring toa 12-ring or greater framework-type. In one embodiment, the molecularsieves used herein have 8-, 10- or 12-ring structures and an averagepore size in the range of from about 3 Å to 15 Å. In a more preferredembodiment, the molecular sieves have 8-rings and an average pore sizeless than about 5 Å, such as in the range of from 3 Å to about 5 Å, forexample from 3 Å to about 4.5 Å, and particularly from 3.5 Å to about4.2 Å.

Molecular sieves have a molecular framework including one, orpreferably, two or more corner-sharing [TO4] tetrahedral units, and morepreferably, two or more [SiO4], [AlO4] and/or [PO4] tetrahedral units.Typically, the molecular sieves used herein are aluminophosphate (AlPO)molecular sieves, silicoaluminophosphate (SAPO) molecular sieves,metal-containing AlPO and SAPO molecular sieves and intergowths of suchsieves.

In the case of metal-containing molecular sieves, the metal atoms can beinserted into the framework of the molecular sieve through a tetrahedralunit, such as [MeO2], and carry a net charge depending on the valencestate of the metal substituent. For example, in one embodiment, when themetal substituent has a valence state of +2, +3, +4, +5, or +6, the netcharge of the tetrahedral unit is between −2 and +2.

Examples of suitable metals for use in the metal-containing molecularsieves used herein are alkali metals of Group 1 of the Periodic Table ofElements, alkaline earth metals of Group 2 of the Periodic Table ofElements, rare earth metal of Group 3 of the Periodic Table of Elements,including the Lanthanides: lanthanum, cerium, praseodymium, neodymium,samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium,thulium, ytterbium and lutetium; and scandium or yttrium, transitionmetals of Groups 4 to 12 of the Periodic Table of Elements, and mixturesof any of these metal species. In one preferred embodiment, the metal isselected from the group consisting of Co, Cr, Cu, Fe, Ga, Ge, Mg, Mn,Ni, Sn, Ti, Zn and Zr, and mixtures thereof. The Periodic Table ofElements referred to herein is the IUPAC format described in the CRCHandbook of Chemistry and Physics, 78th Edition, CRC Press, Boca Raton,Fla. (1997).

Aluminophosphate molecular sieves, silicoaluminophosphate molecularsieves and metal containing derivatives thereof have been described indetail in numerous publications including for example, U.S. Pat. No.4,567,029 (MeAPO where Me is Mg, Mn, Zn, or Co), U.S. Pat. No. 4,440,871(SAPO), European Patent Application EP-A-0 159 624 (ELAPSO where El isAs, Be, B, Cr, Co, Ga, Ge, Fe, Li, Mg, Mn, Ti or Zn), U.S. Pat. No.4,554,143 (FeAPO), U.S. Pat. Nos. 4,822,478, 4,683,217, 4,744,885(FeAPSO), EP-A-0 158 975 and U.S. Pat. No. 4,935,216 (ZnAPSO, EP-A-0 161489 (CoAPSO), EP-A-0 158 976 (ELAPO, where EL is Co, Fe, Mg, Mn, Ti orZn), U.S. Pat. No. 4,310,440 (AlPO4), EP-A-0 158 350 (SENAPSO), U.S.Pat. No. 4,973,460 (LiAPSO), U.S. Pat. No. 4,789,535 (LiAPO), U.S. Pat.No. 4,992,250 (GeAPSO), U.S. Pat. No. 4,888,167 (GeAPO), U.S. Pat. No.5,057,295 (BAPSO), U.S. Pat. No. 4,738,837 (CrAPSO), U.S. Pat. Nos.4,759,919, and 4,851,106 (CrAPO), U.S. Pat. Nos. 4,758,419, 4,882,038,5,434,326 and 5,478,787 (MgAPSO), U.S. Pat. No. 4,554,143 (FeAPO), U.S.Pat. No. 4,894,213 (AsAPSO), U.S. Pat. No. 4,913,888 (AsAPO), U.S. Pat.Nos. 4,686,092, 4,846,956 and 4,793,833 (MnAPSO), U.S. Pat. Nos.5,345,011 and 6,156,931 (MnAPO), U.S. Pat. No. 4,737,353 (BeAPSO), U.S.Pat. No. 4,940,570 (BeAPO), U.S. Pat. Nos. 4,801,309, 4,684,617 and4,880,520 (TiAPSO), U.S. Pat. Nos. 4,500,651, 4,551,236 and 4,605,492(TiAPO), U.S. Pat. Nos. 4,824,554, 4,744,970 (CoAPSO), U.S. Pat. No.4,735,806 (GaAPSO) EP-A-0 293 937 (QAPSO, where Q is framework oxideunit [QO2]), as well as U.S. Pat. Nos. 4,567,029, 4,686,093, 4,781,814,4,793,984, 4,801,364, 4,853,197, 4,917,876, 4,952,384, 4,956,164,4,956,165, 4,973,785, 5,241,093, 5,493,066 and 5,675,050, all of whichare herein fully incorporated by reference.

Other molecular sieves include those described in R. Szostak, Handbookof Molecular Sieves, Van Nostrand Reinhold, New York, N.Y. (1992), whichis herein fully incorporated by reference.

In one embodiment, the molecular sieve, as described in many of the U.S.Patents mentioned above, is represented by the empirical formula, on ananhydrous basis:mR:(M_(x)Al_(y)P_(z))O₂wherein R represents at least one templating agent, preferably anorganic templating agent; m is the number of moles of R per mole of(M_(x)Al_(y)P_(z))O₂ and has a value from 0 to 1, preferably 0 to 0.5,and most preferably from 0 to 0.3; x, y, and z represent the molefraction of Al, P and M as tetrahedral oxides, where M is an elementselected from one of Groups 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,14 and Lanthanide's of the Periodic Table of Elements. Preferably M isselected from Si, Co, Cr, Cu, Fe, Ga, Ge, Mg, Mn, Ni, Sn, Ti, Zn and Zr.In an embodiment, m is greater than or equal to 0.2, and x, y and z aregreater than or equal to 0.01. In another embodiment, m is greater than0.1 to about 1, x is greater than 0 to about 0.25, y is in the range offrom 0.4 to 0.5, and z is in the range of from 0.25 to 0.5, morepreferably m is from 0.15 to 0.7, x is from 0.01 to 0.2, y is from 0.4to 0.5, and z is from 0.3 to 0.5.

Non-limiting examples of SAPO and AlPO molecular sieves useful hereininclude one or a combination of SAPO-5, SAPO-8, SAPO-11, SAPO-16,SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37,SAPO-40, SAPO-41, SAPO-42, SAPO-44 (U.S. Pat. No. 6,162,415), SAPO-47,SAPO-56, AlPO-5, AlPO-11, AlPO-18, AlPO-31, AlPO-34, AlPO-36, AlPO-37,AlPO-46, MCM-2 and metal containing molecular sieves thereof. Of these,particularly useful molecular sieves are one or a combination ofSAPO-18, SAPO-34, SAPO-35, SAPO-44, SAPO-56, AlPO-18 and AlPO-34 andmetal containing derivatives thereof, such as one or a combination ofSAPO-18, SAPO-34, AlPO-34 and AlPO-18, and metal containing derivativesthereof, such as GeAPO-34 and GeAPO-18.

In an embodiment, the molecular sieve is an intergrowth material havingtwo or more distinct crystalline phases within one molecular sievecomposition. In particular, intergrowth molecular sieves are describedin the U.S. Patent Application Publication No. 2002/0165089 andInternational Patent Publication No. WO 98/15496, both of which areherein fully incorporated by reference. For example, SAPO-18, AlPO-18and RUW-18 have an AEI framework-type, and SAPO-34 has a CHAframework-type. Thus the molecular sieve used herein may comprise atleast one intergrowth phase of AEI and CHA framework-types, especiallywhere the ratio of CHA framework-type to AEI framework-type, asdetermined by the DIFFaX method disclosed in U.S. Patent ApplicationPublication No. 2002/0165089, is greater than 1:1.

Molecular Sieve Synthesis

The synthesis of molecular sieves is described in many of the referencesdiscussed above. Generally, molecular sieves are synthesized by thehydrothermal crystallization of one or more of a source of aluminum, asource of phosphorus, a source of silicon and a templating agent, suchas a nitrogen containing organic compound. Typically, a combination ofsources of silicon, aluminum and phosphorus, optionally with one or moretemplating agents, is placed in a sealed pressure vessel, optionallylined with an inert plastic such as polytetrafluoroethylene, and heated,under a crystallization pressure and temperature, until a crystallinematerial is formed, and then recovered by filtration, centrifugationand/or decanting.

Non-limiting examples of silicon sources include silicates, fumedsilica, for example, Aerosil-200 available from Degussa Inc., New York,N.Y., and CAB-O-SIL M-5, organosilicon compounds such as tetraalkylorthosilicates, for example, tetramethyl orthosilicate (TMOS) andtetraethylorthosilicate (TEOS), colloidal silicas or aqueous suspensionsthereof, for example Ludox HS-40 sol available from E.I. du Pont deNemours, Wilmington, Del., silicic acid or any combination thereof.

Non-limiting examples of aluminum sources include aluminum alkoxides,for example aluminum isopropoxide, aluminum phosphate, aluminumhydroxide, sodium aluminate, pseudo-boehmite, gibbsite and aluminumtrichloride, or any combination thereof. A convenient source of aluminumis pseudo-boehmite, particularly when producing a silicoaluminophosphatemolecular sieve.

Non-limiting examples of phosphorus sources, which may also includealuminum-containing phosphorus compositions, include phosphoric acid,organic phosphates such as triethyl phosphate, and crystalline oramorphous aluminophosphates such as AlPO4, phosphorus salts, orcombinations thereof. A convenient source of phosphorus is phosphoricacid, particularly when producing a silicoaluminophosphate.

Templating agents are generally compounds that contain elements of Group15 of the Periodic Table of Elements, particularly nitrogen, phosphorus,arsenic and antimony. Typical templating agents also contain at leastone alkyl or aryl group, such as an alkyl or aryl group having from 1 to10 carbon atoms, for example from 1 to 8 carbon atoms. Preferredtemplating agents are often nitrogen-containing compounds, such asamines, quaternary ammonium compounds and combinations thereof. Suitablequaternary ammonium compounds are represented by the general formulaR4N+, where each R is hydrogen or a hydrocarbyl or substitutedhydrocarbyl group, preferably an alkyl group or an aryl group havingfrom 1 to 10 carbon atoms.

Non-limiting examples of templating agents include tetraalkyl ammoniumcompounds including salts thereof, such as tetramethyl ammoniumcompounds, tetraethyl ammonium compounds, tetrapropyl ammoniumcompounds, and tetrabutylammonium compounds, cyclohexylamine,morpholine, di-n-propylamine (DPA), tripropylamine, triethylamine (TEA),triethanolamine, piperidine, cyclohexylamine, 2-methylpyridine,N,N-dimethylbenzylamine, N,N-diethylethanolamine, dicyclohexylamine,N,N-dimethylethanolamine, choline, N,N′-dimethylpiperazine,1,4-diazabicyclo(2,2,2)octane, N′,N′,N,N-tetramethyl-(1,6)hexanediamine,N-methyldiethanolamine, N-methyl-ethanolamine, N-methyl piperidine,3-methyl-piperidine, N-methylcyclohexylamine, 3-methylpyridine,4-methyl-pyridine, quinuclidine, N,N′-dimethyl-1,4-diazabicyclo(2,2,2)octane ion; di-n-butylamine, neopentylamine, di-n-pentylamine,isopropylamine, t-butyl-amine, ethylenediamine, pyrrolidine, and2-imidazolidone.

The pH of the synthesis mixture containing at a minimum a silicon-,aluminum-, and/or phosphorus-composition, and a templating agent, isgenerally in the range of from 2 to 10, such as from 4 to 9, for examplefrom 5 to 8.

Generally, the synthesis mixture described above is sealed in a vesseland heated, preferably under autogenous pressure, to a temperature inthe range of from about 80° C. to about 250° C., such as from about 100°C. to about 250° C., for example from about 125° C. to about 225° C.,such as from about 150° C. to about 180° C.

In one embodiment, the synthesis of a molecular sieve is aided by seedsfrom another or the same framework type molecular sieve.

The time required to form the crystalline product is usually dependenton the temperature and can vary from immediately up to several weeks.Typically the crystallization time is from about 30 minutes to around 2weeks, such as from about 45 minutes to about 240 hours, for examplefrom about 1 hour to about 120 hours. The hydrothermal crystallizationmay be carried out with or without agitation or stirring.

Once the crystalline molecular sieve product is formed, usually in aslurry state, it may be recovered by any standard technique well knownin the art, for example, by centrifugation or filtration. The recoveredcrystalline product may then be washed, such as with water, and thendried, such as in air.

One method for crystallization involves producing an aqueous reactionmixture containing an excess amount of a templating agent, subjectingthe mixture to crystallization under hydrothermal conditions,establishing an equilibrium between molecular sieve formation anddissolution, and then, removing some of the excess templating agentand/or organic base to inhibit dissolution of the molecular sieve. Seefor example U.S. Pat. No. 5,296,208, which is herein fully incorporatedby reference.

Other methods for synthesizing molecular sieves or modifying molecularsieves are described in U.S. Pat. No. 5,879,655 (controlling the ratioof the templating agent to phosphorus), U.S. Pat. No. 6,005,155 (use ofa modifier without a salt), U.S. Pat. No. 5,475,182 (acid extraction),U.S. Pat. No. 5,962,762 (treatment with transition metal), U.S. Pat.Nos. 5,925,586 and 6,153,552 (phosphorus modified), U.S. Pat. No.5,925,800 (monolith supported), U.S. Pat. No. 5,932,512 (fluorinetreated), U.S. Pat. No. 6,046,373 (electromagnetic wave treated ormodified), U.S. Pat. No. 6,051,746 (polynuclear aromatic modifier), U.S.Pat. No. 6,225,254 (heating template), PCT WO 01/36329 published May 25,2001 (surfactant synthesis), PCT WO 01/25151 published Apr. 12, 2001(staged acid addition), PCT WO 01/60746 published Aug. 23, 2001 (siliconoil), U.S. patent application Ser. No. 09/929,949 filed Aug. 15, 2001(cooling molecular sieve), U.S. patent application Ser. No. 09/615,526filed Jul. 13, 2000 (metal impregnation including copper), U.S. patentapplication Ser. No. 09/672,469 filed Sep. 28, 2000 (conductivemicrofilter), and U.S. patent application Ser. No. 09/754,812 filed Jan.4, 2001 (freeze drying the molecular sieve), which are all herein fullyincorporated by reference.

Where a templating agent is used in the synthesis of the molecularsieve, any templating agent retained in the product may be removed aftercrystallization by numerous well known techniques, for example, bycalcination. Calcination involves contacting the molecular sievecontaining the templating agent with a gas, preferably containingoxygen, at any desired concentration at an elevated temperaturesufficient to either partially or completely remove the templatingagent.

Aluminosilicate and silicoaluminophosphate molecular sieves have eithera high silicon (Si) to aluminum (Al) ratio or a low silicon to aluminumratio, however, a low Si/Al ratio is preferred for SAPO synthesis. Inone embodiment, the molecular sieve has a Si/Al ratio less than 0.65,such as less than 0.40, for example less than 0.32, and particularlyless than 0.20. In another embodiment the molecular sieve has a Si/Alratio in the range of from about 0.65 to about 0.10, such as from about0.40 to about 0.10, for example from about 0.32 to about 0.10, andparticularly from about 0.32 to about 0.15.

Hydrotalcite Additive

Naturally occurring hydrotalcite is a mineral found in relatively smallquantities in a limited number of geographical areas, principally, inNorway and in the Ural Mountains. Natural hydrotalcite has a variablecomposition depending on the location of the source. Naturalhydrotalcite is a hydrated magnesium, aluminum and carbonate-containingcomposition, which has been found to have the typical composition,represented as Mg6Al2(OH)16CO3.4H₂O. Natural hydrotalcite deposits aregenerally found intermeshed with spinel and other minerals, such aspenninite and muscovite, from which it is difficult to separate thenatural hydrotalcite.

Synthetically produced hydrotalcite can be made to have the samecomposition as natural hydrotalcite, or, because of flexibility in thesynthesis, it can be made to have a different composition by replacingthe carbonate anion with other anions, such as phosphate ion. Inaddition, the Mg/Al ratio can be varied to control the basic propertiesof the hydrotalcite.

A phosphate-modified synthetic hydrotalcite and a process for itssynthesis are disclosed in U.S. Pat. No. 4,883,533. U.S. Pat. No.3,539,306 discloses a process for preparing hydrotalcite which involvesmixing an aluminum-containing compound with a magnesium-containingcompound in an aqueous medium in the presence of carbonate ion at a pHof at least 8. U.S. Pat. No. 4,656,156 discloses a process for producingsynthetic hydrotalcite by heating a magnesium compound to a temperatureof about 500 to 900° C. to form activated magnesia, adding the activatedmagnesia to an aqueous solution containing aluminate, carbonate andhydroxyl ions, and then agitating the resultant mixture at a temperatureof about 80 to 100° C. for 20 to 120 minutes to form a low density, highporosity hydrotalcite. A similar process is disclosed in U.S. Pat. No.4,904,457. The entire disclosure of each of the above references isincorporated herein by reference.

Hydrotalcite compositions containing pillaring organic, inorganic andmixed organic/inorganic anions are disclosed in U.S. Pat. No. 4,774,212,the entire disclosure of which is incorporated herein by reference. Thecompositions are anionic magnesium aluminum hydrotalcite clays havinglarge inorganic and/or organic anions located interstitially betweenpositively charged layers of metal hydroxides. The compositions are ofthe formula:[Mg_(2x)Al₂(OH)_(4x+4)]Y_(2/n) ^(n−).ZH₂Owhere Y is a large organic anion selected from the group consisting oflauryl sulfate, p-toluenesulfonate, terephthalate,2,5-dihydroxy-1,4-benzenedisulfonate, and 1,5-naphthalenedisulfonate orwhere Y is an anionic polyoxometalate of vanadium, tungsten ormolybdenum. In the above cases, x is from 1.5 to 2.5, n is 1 or 2 and Zis from 0 to 3, except that when Y is polyoxometalate, n is 6.

An aggregated synthetic hydrotalcite having a substantially spheroidalshape and an average spherical diameter of up to about 60 μm, composedof individual platy particles, is disclosed in U.S. Pat. No. 5,364,828,the entire disclosure of which is incorporated herein by reference. Thisform of hydrotalcite is prepared from aqueous solutions of solublemagnesium and aluminum salts, which are mixed in a molar ratio of fromabout 2.5:1 to 4:1, together with a basic solution containing at least atwo-fold excess of carbonate and a sufficient amount of a base tomaintain a pH of the reaction mixture in the range of from about 8.5 toabout 9.5.

Synthetic hydrotalcite is commercially available and can, for example,be obtained from Sasol North America Inc. as Condea Pural MG70.

Prior to use in the catalyst composition of the invention, it may bedesirable to calcine the hydrotalcite to remove the water inherentlycontained by the material. Suitable calcination conditions include atemperature of from about 300° C. to about 800° C., such as from about400° C. to about 600° C. for about 1 to about 16 hours, such as forabout 3 to about 8 hours.

Rare Earth Metal Component

In addition to the hydrotalcite additive, the molecular sieve catalystcomposition of the invention can also include a rare earth metalcomponent. Suitable rare earth metals include yttrium and elements ofthe Lanthanide or Actinide series metals, including lanthanum, cerium,praseodymium, neodymium, samarium, europium, gadolinium, terbium,dysprosium, holmium, erbium, thulium, ytterbium, lutetium, thorium andmixtures thereof. Typically the rare earth metal will be selected fromlanthanum, yttrium, cerium and mixtures thereof, especially lanthanum.

The rare earth metal component can be present in the final catalystcomposition as the elemental rare earth metal or more preferably, as anoxide of the metal.

Catalyst Composition

The catalyst composition of the invention includes any one of themolecular sieves previously described, hydrotalcite and optionally arare earth metal component. Typically, the catalyst composition containsin the range of from about 10 wt % to about 90 wt %, such as from about40 wt % to about 60 wt %, of the molecular sieve and in the range offrom about 10 wt % to about 90 wt %, such as from about 40 wt % to about60 wt %, of the hydrotalcite based on the total weight of the molecularsieve, the hydrotalcite, and any rare earth metal component present.

Moreover, where the catalyst composition contains a rare earth metalcomponent, said rare earth metal component is typically present in therange of from about 0.1 wt % to about 5 wt %, such as from about 1 wt %to about 3 wt %, based on the total weight of the molecular sieve, thehydrotalcite, and rare earth metal component.

In addition, the catalysts composition can contain a binder and/ormatrix material to enhance the physical characteristics of the catalyst.

There are many different binders that are useful in forming catalystcompositions. Non-limiting examples of binders that are useful alone orin combination include various types of hydrated alumina, silicas,and/or other inorganic oxide sols. One preferred alumina containing solis aluminum chlorhydrol. The inorganic oxide sol acts like glue bindingthe synthesized molecular sieves and other materials such as the matrixtogether, particularly after thermal treatment. Upon heating, theinorganic oxide sol, preferably having a low viscosity, is convertedinto an inorganic oxide binder component. For example, an alumina solwill convert to an aluminum oxide binder following heat treatment.

Aluminum chlorhydrol, a hydroxylated aluminum based sol containing achloride counter ion, has the general formula of AlmOn(OH)oClp.x(H₂O)wherein m is 1 to 20, n is 1 to 8, o is 5 to 40, p is 2 to 15, and x is0 to 30. In one embodiment, the binder is Al13O4(OH)24C17.12(H₂O) as isdescribed in G. M. Wolterman, et al., Stud. Surf. Sci. and Catal., 76,pages 105-144 (1993), which is herein incorporated by reference. Inanother embodiment, one or more binders are combined with one or moreother non-limiting examples of alumina materials such as aluminumoxyhydroxide, γ-alumina, boehmite, diaspore, and transitional aluminassuch as α-alumina, β-alumina, γ-alumina, δ-alumina, ε-alumina,κ-alumina, and ρ-alumina, aluminum trihydroxide, such as gibbsite,bayerite, nordstrandite, doyelite, and mixtures thereof.

In another embodiment, the binder is an alumina sol, predominantlycomprising aluminum oxide, optionally including some silicon. In yetanother embodiment, the binder is peptized alumina made by treating analumina hydrate, such as pseudobohemite, with an acid, preferably anacid that does not contain a halogen, to prepare a sol or aluminum ionsolution. Non-limiting examples of commercially available colloidalalumina sols include Nalco 8676 available from Nalco Chemical Co.,Naperville, Ill., and Nyacol AL20DW available from Nyacol NanoTechnologies, Inc., Ashland, Mass.

Non-limiting examples of matrix materials include one or more non-activemetal oxides including beryllia, quartz, silica or sols, and mixturesthereof, for example silica-magnesia, silica-zirconia, silica-titania,silica-alumina and silica-alumina-thoria. In an embodiment, matrixmaterials are natural clays such as those from the families ofmontmorillonite and kaolin. These natural clays include subbentonitesand those kaolins known as, for example, Dixie, McNamee, Georgia andFlorida clays. Non-limiting examples of other matrix materials includehaloysite, kaolinite, dickite, nacrite, or anauxite. The matrixmaterial, such as a clay, may be subjected to well known modificationprocesses such as calcination and/or acid treatment and/or chemicaltreatment.

Where the catalyst composition contains a binder and/or matrix material,the catalyst composition typically contains from about 1% to about 80%,such as from about 5% to about 60%, and particularly from about 5% toabout 50%, by weight of the molecular sieve based on the total weight ofthe catalyst composition. Where the catalyst composition contains abinder and a matrix material, the weight ratio of the binder to thematrix material is typically from 1:15 to 1:5, such as from 1:10 to 1:4,and particularly from 1:6 to 1:5.

Method of Making the Catalyst Composition

The catalyst composition used herein can be prepared using a variety ofmethods. In general, however, making the catalyst composition comprisesinitially synthesizing the molecular sieve and then combining themolecular sieve with a hydrotalcite composition comprising thehydrotalcite and, where desired, a rare earth metal component. Combiningthe molecular sieve with a hydrotalcite composition is convenientlyachieved by forming a slurry of the molecular sieve and the hydrotalcitecomposition in a liquid, mixing the slurry, for example by colloidmilling, to produce a substantially homogeneous mixture and then dryingthe mixture. Non-limiting examples of suitable liquids include one or acombination of water, alcohol, ketones, aldehydes, and/or esters. Themost preferred liquid is water.

Where the hydrotalcite composition contains a rare earth metalcomponent, it is conveniently produced by dissolving a rare earthcompound in a solvent, such as water, combining the resultant solutionwith the hydrotalcite either by impregnation or slurry mixing and thendrying the resultant mixture. Suitable rare earth metal compoundsinclude acetates, halides, oxides, oxyhalides, hydroxides, sulfides,sulfonates, borides, borates, carbonates, nitrates, carboxylates andmixtures thereof.

Where the catalyst composition contains a matrix and/or binder, themolecular sieve is conveniently initially formulated into a catalystprecursor with the matrix and/or binder and hydrotalcite composition isthen combined with the formulated precursor. In one embodiment, themolecular sieve composition and the matrix material, optionally with abinder, are combined with a liquid to form a slurry and then mixed, suchas by colloid milling, to produce a substantially homogeneous mixturecontaining the molecular sieve composition. Non-limiting examples ofsuitable liquids include one or a combination of water, alcohol,ketones, aldehydes, and/or esters. The most preferred liquid is water.

The resultant catalyst composition can then be formed into useful shapedand sized particles by well-known techniques such as spray drying,pelletizing, extrusion, and the like.

Once the molecular sieve catalyst composition is formed in asubstantially dry or dried state, to further harden and/or activate theformed catalyst composition, a heat treatment such as calcination, at anelevated temperature is usually performed. Typical calcinationtemperatures are in the range from about 400° C. to about 1,000° C.,such as from about 500° C. to about 800° C., such as from about 550° C.to about 700° C. Typical calcination environments are air (which mayinclude a small amount of water vapor), nitrogen, helium, flue gas(combustion product lean in oxygen), or any combination thereof.

Process for Using the Molecular Sieve Catalyst Compositions

The catalyst compositions described above are useful in a variety ofprocesses including the conversion of a feedstock containing one of morealiphatic compounds, preferably oxygenates, to olefins and theconversion of a feedstock including one or more oxygenates and ammoniainto alkyl amines, in particular methylamines.

The most preferred process of the invention is a process directed to theconversion of an aliphatic feedstock to one or more olefin(s).Typically, the feedstock contains one or more aliphatic-containingcompounds such that the aliphatic moiety contains from 1 to about 50carbon atoms, such as from 1 to 20 carbon atoms, for example from 1 to10 carbon atoms, and particularly from 1 to 4 carbon atoms.

Non-limiting examples of aliphatic-containing compounds include alcoholssuch as methanol and ethanol, alkyl mercaptans such as methyl mercaptanand ethyl mercaptan, alkyl sulfides such as methyl sulfide, alkylaminessuch as methylamine, alkyl ethers such as dimethyl ether, diethyl etherand methylethyl ether, alkyl halides such as methyl chloride and ethylchloride, alkyl ketones such as dimethyl ketone, formaldehydes, andvarious acids such as acetic acid.

In a preferred embodiment of the process of the invention, the feedstockcontains one or more oxygenates, more specifically, one or more organiccompound(s) containing at least one oxygen atom. In the most preferredembodiment of the process of invention, the oxygenate in the feedstockis one or more alcohol(s), preferably aliphatic alcohol(s) where thealiphatic moiety of the alcohol(s) has from 1 to 20 carbon atoms,preferably from 1 to 10 carbon atoms, and most preferably from 1 to 4carbon atoms. The alcohols useful as feedstock in the process of theinvention include lower straight and branched chain aliphatic alcoholsand their unsaturated counterparts.

Non-limiting examples of oxygenates include methanol, ethanol,n-propanol, isopropanol, methyl ethyl ether, dimethyl ether, diethylether, di-isopropyl ether, formaldehyde, dimethyl carbonate, dimethylketone, acetic acid, and mixtures thereof.

In the most preferred embodiment, the feedstock is selected from one ormore of methanol, ethanol, dimethyl ether, diethyl ether or acombination thereof, more preferably methanol and dimethyl ether, andmost preferably methanol.

The various feedstocks discussed above, particularly a feedstockcontaining an oxygenate, more particularly a feedstock containing analcohol, is converted primarily into one or more olefin(s). Theolefin(s) produced from the feedstock typically have from 2 to 30 carbonatoms, preferably 2 to 8 carbon atoms, more preferably 2 to 6 carbonatoms, still more preferably 2 to 4 carbons atoms, and most preferablyare ethylene and/or propylene.

The catalyst composition of the invention is particularly useful in theprocess that is generally referred to as the gas-to-olefins (GTO)process or alternatively, the methanol-to-olefins (MTO) process. In thisprocess, an oxygenated feedstock, most preferably a methanol-containingfeedstock, is converted in the presence of a molecular sieve catalystcomposition into one or more olefin(s), preferably and predominantly,ethylene and/or propylene.

Using the catalyst composition of the invention for the conversion of afeedstock, preferably a feedstock containing one or more oxygenates, theamount of olefin(s) produced based on the total weight of hydrocarbonproduced is typically greater than 50 weight percent, for examplegreater than 60 weight percent, such as greater than 70 weight percent.Moreover, the amount of ethylene and/or propylene produced based on thetotal weight of hydrocarbon product produced is typically greater than40 weight percent, such as greater than 50 weight percent, for examplegreater than 65 weight percent. Typically, the amount ethylene producedin weight percent based on the total weight of hydrocarbon productproduced, is typically greater than 20 weight percent, such as greaterthan 30 weight percent. In addition, the amount of propylene produced inweight percent based on the total weight of hydrocarbon product producedis typically greater than 30 weight percent, such as greater than 40weight percent.

In addition to the oxygenate component, such as methanol, the feedstockmay contains one or more diluent(s), which are generally non-reactive tothe feedstock or molecular sieve catalyst composition and are typicallyused to reduce the concentration of the feedstock. Non-limiting examplesof diluents include helium, argon, nitrogen, carbon monoxide, carbondioxide, water, essentially non-reactive paraffins (especially alkanessuch as methane, ethane, and propane), essentially non-reactive aromaticcompounds, and mixtures thereof. The most preferred diluents are waterand nitrogen, with water being particularly preferred.

The diluent, for example water, may be used either in a liquid or avapor form, or a combination thereof. The diluent may be either addeddirectly to the feedstock entering a reactor or added directly to thereactor, or added with the molecular sieve catalyst composition.

The present process can be conducted over a wide range of temperatures,such as in the range of from about 200° C. to about 1000° C., forexample from about 250° C. to about 800° C., including from about 250°C. to about 750° C., conveniently from about 300° C. to about 650° C.,typically from about 350° C. to about 600° C. and particularly fromabout 350° C. to about 550° C.

Similarly, the present process can be conducted over a wide range ofpressures including autogenous pressure. Typically the partial pressureof the feedstock exclusive of any diluent therein employed in theprocess is in the range of from about 0.1 kPaa to about 5 MPaa, such asfrom about 5 kPaa to about 1 MPaa, and conveniently from about 20 kPaato about 500 kPaa.

The weight hourly space velocity (WHSV), defined as the total weight offeedstock excluding any diluents per hour per weight of molecular sievein the catalyst composition, typically ranges from about 1 hr-1 to about5000 hr-1, such as from about 2 hr-1 to about 3000 hr-1, for examplefrom about 5 hr-1 to about 1500 hr-1, and conveniently from about 10hr-1 to about 1000 hr-1. In one embodiment, the WHSV is greater than 20hr-1 and, where feedstock contains methanol and/or dimethyl ether, is inthe range of from about 20 hr-1 to about 300 hr-1.

Where the process is conducted in a fluidized bed, the superficial gasvelocity (SGV) of the feedstock including diluent and reaction productswithin the reactor system, and particularly within a riser reactor(s),is at least 0.1 meter per second (m/sec), such as greater than 0.5m/sec, such as greater than 1 m/sec, for example greater than 2 m/sec,conveniently greater than 3 m/sec, and typically greater than 4 m/sec.See for example U.S. patent application Ser. No. 09/708,753 filed Nov.8, 2000, which is herein incorporated by reference.

The process of the invention is conveniently conducted as a fixed bedprocess, or more typically as a fluidized bed process (including aturbulent bed process), such as a continuous fluidized bed process, andparticularly a continuous high velocity fluidized bed process.

The process can take place in a variety of catalytic reactors such ashybrid reactors that have a dense bed or fixed bed reaction zones and/orfast fluidized bed reaction zones coupled together, circulatingfluidized bed reactors, riser reactors, and the like. Suitableconventional reactor types are described in for example U.S. Pat. No.4,076,796, U.S. Pat. No. 6,287,522 (dual riser), and FluidizationEngineering, D. Kunii and O. Levenspiel, Robert E. Krieger PublishingCompany, New York, N.Y. 1977, which are all herein fully incorporated byreference.

The preferred reactor types are riser reactors generally described inRiser Reactor, Fluidization and Fluid-Particle Systems, pages 48 to 59,F. A. Zenz and D. F. Othmo, Reinhold Publishing Corporation, New York,1960, and U.S. Pat. No. 6,166,282 (fast-fluidized bed reactor), and U.S.patent application Ser. No. 09/564,613 filed May 4, 2000 (multiple riserreactor), which are all herein fully incorporated by reference.

In one practical embodiment, the process is conducted as a fluidized bedprocess or high velocity fluidized bed process utilizing a reactorsystem, a regeneration system and a recovery system.

In such a process the reactor system would conveniently include a fluidbed reactor system having a first reaction zone within one or more riserreactor(s) and a second reaction zone within at least one disengagingvessel, typically comprising one or more cyclones. In one embodiment,the one or more riser reactor(s) and disengaging vessel are containedwithin a single reactor vessel. Fresh feedstock, preferably containingone or more oxygenates, optionally with one or more diluent(s), is fedto the one or more riser reactor(s) into which a molecular sievecatalyst composition or coked version thereof is introduced. In oneembodiment, prior to being introduced to the riser reactor(s), themolecular sieve catalyst composition or coked version thereof iscontacted with a liquid, preferably water or methanol, and/or a gas, forexample, an inert gas such as nitrogen.

In an embodiment, the amount of fresh feedstock fed as a liquid and/or avapor to the reactor system is in the range of from 0.1 weight percentto about 85 weight percent, such as from about 1 weight percent to about75 weight percent, more typically from about 5 weight percent to about65 weight percent based on the total weight of the feedstock includingany diluent contained therein. The liquid and vapor feedstocks may bethe same composition, or may contain varying proportions of the same ordifferent feedstocks with the same or different diluents.

The feedstock entering the reactor system is preferably converted,partially or fully, in the first reactor zone into a gaseous effluentthat enters the disengaging vessel along with the coked catalystcomposition. In the preferred embodiment, cyclone(s) are provided withinthe disengaging vessel to separate the coked catalyst composition fromthe gaseous effluent containing one or more olefin(s) within thedisengaging vessel. Although cyclones are preferred, gravity effectswithin the disengaging vessel can also be used to separate the catalystcomposition from the gaseous effluent. Other methods for separating thecatalyst composition from the gaseous effluent include the use ofplates, caps, elbows, and the like.

In one embodiment, the disengaging vessel includes a stripping zone,typically in a lower portion of the disengaging vessel. In the strippingzone the coked catalyst composition is contacted with a gas, preferablyone or a combination of steam, methane, carbon dioxide, carbon monoxide,hydrogen, or an inert gas such as argon, preferably steam, to recoveradsorbed hydrocarbons from the coked catalyst composition that is thenintroduced to the regeneration system.

The coked catalyst composition is withdrawn from the disengaging vesseland introduced to the regeneration system. The regeneration systemcomprises a regenerator where the coked catalyst composition iscontacted with a regeneration medium, preferably a gas containingoxygen, under conventional regeneration conditions of temperature,pressure and residence time.

Non-limiting examples of suitable regeneration media include one or moreof oxygen, O3, SO3, N20, NO, NO2, N2O5, air, air diluted with nitrogenor carbon dioxide, oxygen and water (U.S. Pat. No. 6,245,703), carbonmonoxide and/or hydrogen. Suitable regeneration conditions are thosecapable of burning coke from the coked catalyst composition, preferablyto a level less than 0.5 weight percent based on the total weight of thecoked molecular sieve catalyst composition entering the regenerationsystem. For example, the regeneration temperature may be in the range offrom about 200° C. to about 1500° C., such as from about 300° C. toabout 1000° C., for example from about 450° C. to about 750° C., andconveniently from about 550° C. to 700° C. The regeneration pressure maybe in the range of from about 15 psia (103 kPaa) to about 500 psia (3448kpaa), such as from about 20 psia (138 kpaa) to about 250 psia (1724kPaa), including from about 25 psia (172 kPaa) to about 150 psia (1034kpaa), and conveniently from about 30 psia (207 kpaa) to about 60 psia(414 kpaa).

The residence time of the catalyst composition in the regenerator may bein the range of from about one minute to several hours, such as fromabout one minute to 100 minutes, and the volume of oxygen in theregeneration gas may be in the range of from about 0.01 mole percent toabout 5 mole percent based on the total volume of the gas.

The burning of coke in the regeneration step is an exothermic reaction,and in an embodiment, the temperature within the regeneration system iscontrolled by various techniques in the art including feeding a cooledgas to the regenerator vessel, operated either in a batch, continuous,or semi-continuous mode, or a combination thereof. A preferred techniqueinvolves withdrawing the regenerated catalyst composition from theregeneration system and passing it through a catalyst cooler to form acooled regenerated catalyst composition. The catalyst cooler, in anembodiment, is a heat exchanger that is located either internal orexternal to the regeneration system. Other methods for operating aregeneration system are disclosed in U.S. Pat. No. 6,290,916(controlling moisture), which is herein fully incorporated by reference.

The regenerated catalyst composition withdrawn from the regenerationsystem, preferably from a catalyst cooler, is combined with a freshmolecular sieve catalyst composition and/or re-circulated molecularsieve catalyst composition and/or feedstock and/or fresh gas or liquids,and returned to the riser reactor(s). In one embodiment, the regeneratedcatalyst composition withdrawn from the regeneration system is returnedto the riser reactor(s) directly, preferably after passing through acatalyst cooler. A carrier, such as an inert gas, feedstock vapor, steamor the like, may be used, semi-continuously or continuously, tofacilitate the introduction of the regenerated catalyst composition tothe reactor system, preferably to the one or more riser reactor(s).

By controlling the flow of the regenerated catalyst composition orcooled regenerated catalyst composition from the regeneration system tothe reactor system, the optimum level of coke on the molecular sievecatalyst composition entering the reactor is maintained. There are manytechniques for controlling the flow of a catalyst composition describedin Michael Louge, Experimental Techniques, Circulating Fluidized Beds,Grace, Avidan and Knowlton, eds., Blackie, 1997 (336-337), which isherein incorporated by reference.

Coke levels on the catalyst composition are measured by withdrawing thecatalyst composition from the conversion process and determining itscarbon content. Typical levels of coke on the molecular sieve catalystcomposition, after regeneration, are in the range of from 0.01 weightpercent to about 15 weight percent, such as from about 0.1 weightpercent to about 10 weight percent, for example from about 0.2 weightpercent to about 5 weight percent, and conveniently from about 0.3weight percent to about 2 weight percent based on the weight of themolecular sieve.

The gaseous effluent is withdrawn from the disengaging system and ispassed through a recovery system. There are many well known recoverysystems, techniques and sequences that are useful in separatingolefin(s) and purifying olefin(s) from the gaseous effluent. Recoverysystems generally comprise one or more or a combination of variousseparation, fractionation and/or distillation towers, columns,splitters, or trains, reaction systems such as ethylbenzene manufacture(U.S. Pat. No. 5,476,978) and other derivative processes such asaldehydes, ketones and ester manufacture (U.S. Pat. No. 5,675,041), andother associated equipment, for example various condensers, heatexchangers, refrigeration systems or chill trains, compressors,knock-out drums or pots, pumps, and the like.

Non-limiting examples of these towers, columns, splitters or trains usedalone or in combination include one or more of a demethanizer,preferably a high temperature demethanizer, a de-ethanizer, adepropanizer, a wash tower often referred to as a caustic wash towerand/or quench tower, absorbers, adsorbers, membranes, ethylene (C2)splitter, propylene (C3) splitter, butene (C4) splitter, and the like.

Various recovery systems useful for recovering predominantly olefin(s),preferably light olefin(s) such as ethylene, propylene and/or butene,are described in U.S. Pat. No. 5,960,643 (secondary rich ethylenestream), U.S. Pat. Nos. 5,019,143, 5,452,581 and 5,082,481 (membraneseparations), U.S. Pat. No. 5,672,197 (pressure dependent adsorbents),U.S. Pat. No. 6,069,288 (hydrogen removal), U.S. Pat. No. 5,904,880(recovered methanol to hydrogen and carbon dioxide in one step), U.S.Pat. No. 5,927,063 (recovered methanol to gas turbine power plant), andU.S. Pat. No. 6,121,504 (direct product quench), U.S. Pat. No. 6,121,503(high purity olefins without superfractionation), and U.S. Pat. No.6,293,998 (pressure swing adsorption), which are all herein fullyincorporated by reference.

Using the catalyst composition of the invention for the conversion of afeedstock containing one or more oxygenates into olefin(s), it is foundthat the life of the catalyst is improved as compared with a similarcatalyst without the hydrotalcite additive. Typically, the improvementis such that the life of the catalyst of the invention is at least 50%,such as at least 100%, for example at least 200%, greater than that ofthe catalyst without the hydrotalcite additive.

The catalyst composition described herein can also be used in themanufacture of alkylamines, using a feedstock including ammonia inaddition to oxygenates. Examples of suitable processes are described inEP 0 993 867 A1, and in U.S. Pat. No. 6,153,798.

The invention will now be more particularly described with reference tothe Examples, in which all parts are by weight.

Example 1 Synthesis of EMM-2

To 165.5 parts of demineralized water were added 228.4 parts of an 85%solution of H3PO4. 103 parts of water were used to rinse the container.To this diluted solution were added 14.9 parts of Ludox AS40 and 2.1parts of water were used to rinse the container. Then 416.7 parts of a35% solution of TEAOH (tetraethylammonium hydroxide) were added and 24.8parts of rinse water were used to rinse the container. Finally 133.2parts of Condea Pural SB were added and mixed until a homogeneousmixture was obtained, whereafter the container was rinsed with 4.1 partsof water.

The resultant homogeneous mixture was crystallized in a stirredautoclave with stirring rate of 50 rpm. The autoclave was heated in 12.5hours to 175° C. and was kept at that temperature for 50 hours to effectthe crystallization. The resultant EMM-2 crystals were recovered bywashing and drying. After drying the material overnight at 120° C., 21.3wt % (based on the initial intake) of solids were recovered. Theresultant material was then calcined first in nitrogen at 650° C. for 5hours, followed by air calcination for 3 hours at 650° C.

Example 2 EMM-2 with La/Hydrotalcite

0.23 gram of lanthanum acetate was dissolved in 1.9 ml of de-ionizedwater and the resulting solution was added drop-wise to 2.015 gram ofhydrotalcite as supplied by Sasol North America Inc. as Condea PuralMG70 (specific surface area of 180 m2/gram). The treated hydrotalcitewas dried at 50° C. for 1 hour under vacuum and then calcined in air at550° C. for 3 hours.

0.2 gram of the La-impregnated hydrotalcite was mixed with 0.36 gram ofthe calcined EMM-2 from Example 1 and the resultant catalyst wasevaluated in the conversion of methanol to olefins in a fixed bedreactor equipped with an on-line gas chromatograph for product analysis.The test conditions were 450° C., 25 psig (273 kpaa) and 25 WHSV. Theresults of the test are summarized in Table 1 which also shows theresults obtained with a comparative test using 0.36 gram of EMM-2 aloneunder the same conditions. TABLE 1 EMM-2 + Catalyst EMM-2La/Hydrotalcite C2═ (wt % of product) 35.3 32.3 C3═ (wt % of product)41.0 43.7 C₂═ + C₃═ (wt % of product) 76.3 76.0 Catalyst Life 20.7 72.3

It is clear from Table 1 that the addition of the La/hydrotalcite to theEMM-2 increased the life of the catalyst and also increased itspropylene selectivity at the expense of its ethylene selectivity. Thetotal ethylene plus propylene selectivity was substantially unaffected.The catalyst life is defined as the total amount of methanol convertedin grams per gram of EMM-2.

Example 3 Synthesis of Ge APO-34/18 Intergrowth

21.8 grams of H3PO4 (85%) were diluted with 22.1 grams of de-ionizedwater and to this solution were added 3.6 grams of Ge-ethoxide. Aftermixing this solution, 40.1 grams of TEAOH (35%) were added dropwise tothe solution, whereafter 12.8 grams of Condea Pural SB were added andmixed until a homogeneous mixture was obtained. 85.8 grams of thismixture was transferred to a 150 ml stainless steel autoclave andmounted on an axis inside a oven. The autoclave was rotated at 60 rpmwhile the oven was heated in 8 hours from room temperature to 175° C.and then kept at this temperature for 48 hours. After crystallization,the resultant GeAPO-34/18 intergrowth product was washed and dried. 18.9wt % of solid yield was recovered after drying overnight at 120° C. TheAEI/CHA of ratio of the recovered intergrowth material was 90:10. Thefinal product was calcined first in nitrogen at 650° C. for 5 hours,followed by air calcination for 3 hours at 650° C.

Example 4 Ge-AP034/18 with La/Hydrotalcite

0.61 gram of lanthanum chloride was dissolved in 4.72 ml of de-ionizedwater and the resulting solution was added drop-wise to 5.00 gram ofhydrotalcite as supplied by Sasol North America Inc. as Condea PuralMG70 (specific surface area of 180 m2/gram). The treated hydrotalcitewas dried at 50° C. for 1 hour under vacuum and then calcined in air at550° C. for 3 hours.

0.2 gram of the La-impregnated hydrotalcite produced above was mixedwith 0.36 gram of the calcined GeAPO-34/18 of Example 3 and theresultant catalyst was evaluated in the conversion of methanol toolefins in a fixed bed reactor equipped with an on-line gaschromatograph for product analysis. The test conditions were 450° C., 25psig (273 kpaa) and 25 WHSV. The results of the test are summarized inTable 2 which also shows the results obtained under the same conditionswith (a) a catalyst consisting solely of 0.36 gram of GeAPO-34/18 and(b) a catalyst comprising 0.36 gram of GeAPO-34/18 and 0.2 gram ofcalcined hydrotalcite (no La impregnation). TABLE 2 GeAPO- GeAPO-34/18 +GeAPO-34/18 + Catalyst 34/18 Hydrotalcite La/Hydrotalcite C₂═ (wt % of31.5 29.4 27.9 product) C₃═ (wt % of 43.6 44.3 46.3 product) C₂═ + C₃═(wt % of 75.0 73.7 74.2 product) Catalyst Life 38.9 82.0 107.9

It is clear from Table 2 that the addition of the hydrotalcite to theGeAPO-34/18 increased the life of the catalyst by over 100%, whereas theaddition of La/hydrotalcite increased the life of the catalyst by over170%.

While the present invention has been described and illustrated byreference to particular embodiments, those of ordinary skill in the artwill appreciate that the invention lends itself to variations notnecessarily illustrated herein. For example, it is contemplated that thecatalyst compositions described herein are useful in other processes,such as catalytic cracking. For this reason, reference should be madesolely to the appended claims for purposes of determining the true scopeof the present invention.

1-33. (canceled)
 34. A process for converting a hydrocarbon oxygenatefeedstock to olefins, the process comprising contacting the feedstockwith a catalyst composition comprising: (a) a molecular sieve; and (b)hydrotalcite; under catalytic conversion conditions, to form a productmixture comprising olefins.
 35. The process of claim 34, wherein themolecular sieve is selected from silicoaluminophosphates,aluminophosphates, metal-containing forms thereof and mixtures,including intergrowths, thereof.
 36. The process of claim 34, whereinthe molecular sieve is selected from SAPO-5, SAPO-8, SAPO-11, SAPO-16,SAPO-17, SAPO-18, SAPO-20, SAPO-31, SAPO-34, SAPO-35, SAPO-36, SAPO-37,SAPO-40, SAPO-41, SAPO-42, SAPO-44, SAPO-47, SAPO-56, AlPO-5, AlPO-11,AlPO-18, AlPO-31, AlPO-34, AlPO-36, AlPO-37, AlPO-46, MCM-2,metal-containing forms thereof, and mixtures, including intergrowths,thereof.
 37. The process of claim 34, wherein the molecular sieve isselected from SAPO-18, SAPO-34, SAPO-35, SAPO-44, SAPO-47, ALPO-34,metal-containing forms thereof, and mixtures, including intergrowths,thereof.
 38. The process of claim 34, wherein the molecular sieve isSAPO-34, SAPO-18, an intergrowth of SAPO-34 and SAPO-18, GeAPO-34,GeAPO-18 or an intergrowth of GeAPO-34 and GeAPO-18
 39. The process ofclaim 34, wherein the catalyst composition comprises the molecular sievein an amount of from 10 to 90 wt %, and the hydrotalcite in an amount offrom 10 to 90 wt %, wherein the weight percents are based on the totalweight of the molecular sieve and the hydrotalcite.
 40. The process ofclaim 34, wherein the catalyst composition further comprises a rareearth metal component.
 41. The process of claim 40, wherein the catalystcomposition comprises the molecular sieve in an amount of from 10 to 90wt %, the hydrotalcite in an amount of from 10 to 90 wt %, and the rareearth metal component in an amount of from 0.1 to 5 wt %, wherein theweight percents are based on the total weight of the molecular sieve,the hydrotalcite and the rare earth metal component.
 42. The process ofclaim 40, wherein the rare earth metal component is lanthanum.
 43. Theprocess of claim 34, wherein the feedstock comprises methanol andproduct mixture comprises ethylene and propylene.